import java.util.Scanner;

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        int a = in.nextInt();
        int b = in.nextInt();
        int sum = a + b;
        int n = 1;
        for (int i = 0; i < a; i++) {
            n = n * (sum - i) / (i + 1);
        }

        System.out.println(n);
    }
}